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50-554: The Ahklun Mountains have many lakes, some more than 1,300 feet (400 m) deep. The mountains cover approximately 80 percent of the Togiak National Wildlife Refuge. The refuge also contains tundra and coastal plains . The Ahklun Mountains are dominated by alpine tundra , heath , and barrens, while moist sedge - tussock meadows occur in valley bottoms. Black spruce forest occurs on some hills and ridges. Forests of white spruce , paper birch , and alder cover

100-537: A temperate grassland , restricting southern tundra to coastal Antarctica and its islands. The flora and fauna of Antarctica and the Antarctic Islands (south of 60° south latitude) are protected by the Antarctic Treaty . Alpine tundra does not contain trees because the climate and soils at high altitude block tree growth. The cold climate of the alpine tundra is caused by the low air temperatures, and

150-415: A carbon dioxide removal solution is under debate. An important mitigation measure is "preserving and enhancing carbon sinks". This refers to the management of Earth's natural carbon sinks in a way that preserves or increases their capability to remove CO 2 from the atmosphere and to store it durably. Scientists call this process also carbon sequestration . In the context of climate change mitigation,

200-750: A local climate in which at least one month has an average temperature high enough to melt snow (0 °C (32 °F)), but no month with an average temperature in excess of 10 °C (50 °F). The cold limit generally meets the EF climates of permanent ice and snows ; the warm-summer limit generally corresponds with the poleward or altitudinal limit of trees, where they grade into the subarctic climates designated Dfd , Dwd and Dsd (extreme winters as in parts of Siberia ), Dfc typical in Alaska, Canada, mountain areas of Scandinavia , European Russia , and Western Siberia (cold winters with months of freezing). Despite

250-541: A majority of ocean plant life and store large quantities of carbon. Deep blue carbon is located in international waters and includes carbon contained in "continental shelf waters, deep-sea waters and the sea floor beneath them". For climate change mitigation purposes, the maintenance and enhancement of natural carbon sinks, mainly soils and forests, is important. In the past, human practices like deforestation and industrial agriculture have depleted natural carbon sinks. This kind of land use change has been one of

300-505: A nutrient desert. Grasslands contribute to soil organic matter , stored mainly in their extensive fibrous root mats. Due in part to the climatic conditions of these regions (e.g., cooler temperatures and semi-arid to arid conditions), these soils can accumulate significant quantities of organic matter. This can vary based on rainfall, the length of the winter season, and the frequency of naturally occurring lightning-induced grass-fires . While these fires release carbon dioxide, they improve

350-400: A precursor of a greenhouse gas from the atmosphere ". These sinks form an important part of the natural carbon cycle . An overarching term is carbon pool , which is all the places where carbon on Earth can be, i.e. the atmosphere , oceans , soil , florae , fossil fuel reservoirs and so forth. A carbon sink is a type of carbon pool that has the capability to take up more carbon from

400-500: A reduced effect on global warming. For example, nitrous oxide can be reduced to harmless N 2 . Related terms are "carbon pool, reservoir, sequestration , source and uptake". The same publication defines carbon pool as "a  reservoir in the Earth system where elements, such as carbon [...], reside in various chemical forms for a period of time." Both carbon pools and carbon sinks are important concepts in understanding

450-490: Is a concept within climate change mitigation that refers to "biologically driven carbon fluxes and storage in marine systems that are amenable to management". Most commonly, it refers to the role that tidal marshes , mangroves and seagrass meadows can play in carbon sequestration . These ecosystems can play an important role for climate change mitigation and ecosystem-based adaptation . However, when blue carbon ecosystems are degraded or lost, they release carbon back to

500-479: Is a risk of wildfire, such as the 1,039 km (401 sq mi) of tundra which burned in 2007 on the north slope of the Brooks Range in Alaska. Such events may both result from and contribute to global warming. Carbon emissions from permafrost thaw contribute to the same warming which facilitates the thaw, making it a positive climate change feedback . The warming also intensifies Arctic water cycle , and

550-449: Is characterized by plants that grow close to the ground, including perennial grasses , sedges , forbs , cushion plants , mosses , and lichens . The flora is adapted to the harsh conditions of the alpine environment, which include low temperatures, dryness, ultraviolet radiation, and a short growing season. Tundra climates ordinarily fit the Köppen climate classification ET , signifying

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600-948: Is degraded by chemical weathering and biological degradation . More recalcitrant organic carbon polymers such as cellulose , hemi-cellulose , lignin , aliphatic compounds, waxes and terpenoids are collectively retained as humus . Organic matter tends to accumulate in litter and soils of colder regions such as the boreal forests of North America and the Taiga of Russia . Leaf litter and humus are rapidly oxidized and poorly retained in sub-tropical and tropical climate conditions due to high temperatures and extensive leaching by rainfall. Areas, where shifting cultivation or slash and burn agriculture are practiced, are generally only fertile for two to three years before they are abandoned. These tropical jungles are similar to coral reefs in that they are highly efficient at conserving and circulating necessary nutrients, which explains their lushness in

650-408: Is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: Arctic tundra, alpine tundra , and Antarctic tundra. Tundra vegetation is composed of dwarf shrubs , sedges , grasses , mosses , and lichens . Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as

700-771: Is home to several peoples who are mostly nomadic reindeer herders, such as the Nganasan and Nenets in the permafrost area (and the Sami in Sápmi ). Arctic tundra contains areas of stark landscape and is frozen for much of the year. The soil there is frozen from 25 to 90 cm (10 to 35 in) down, making it impossible for trees to grow there. Instead, bare and sometimes rocky land can only support certain kinds of Arctic vegetation , low-growing plants such as moss, heath ( Ericaceae varieties such as crowberry and black bearberry ), and lichen . There are two main seasons, winter and summer, in

750-630: Is light, evaporation is also relatively minimal. During the summer, the permafrost thaws just enough to let plants grow and reproduce, but because the ground below this is frozen, the water cannot sink any lower, so the water forms the lakes and marshes found during the summer months. There is a natural pattern of accumulation of fuel and wildfire which varies depending on the nature of vegetation and terrain. Research in Alaska has shown fire-event return intervals (FRIs) that typically vary from 150 to 200 years, with dryer lowland areas burning more frequently than wetter highland areas. The biodiversity of tundra

800-694: Is low: 1,700 species of vascular plants and only 48 species of land mammals can be found, although millions of birds migrate there each year for the marshes. There are also a few fish species. There are few species with large populations. Notable plants in the Arctic tundra include blueberry ( Vaccinium uliginosum ), crowberry ( Empetrum nigrum ), reindeer lichen ( Cladonia rangiferina ), lingonberry ( Vaccinium vitis-idaea ), and Labrador tea ( Rhododendron groenlandicum ). Notable animals include reindeer (caribou), musk ox , Arctic hare , Arctic fox , snowy owl , ptarmigan , northern red-backed voles , lemmings ,

850-404: Is similar to polar climate . Alpine tundra is generally better drained than arctic soils. Alpine tundra transitions to subalpine forests below the tree line; stunted forests occurring at the forest-tundra ecotone (the treeline ) are known as Krummholz . Alpine tundra can be affected by woody plant encroachment . Alpine tundra occurs in mountains worldwide. The flora of the alpine tundra

900-424: Is that forests can turn from sinks to carbon sources. In 2019 forests took up a third less carbon than they did in the 1990s, due to higher temperatures, droughts and deforestation . The typical tropical forest may become a carbon source by the 2060s. Researchers have found that, in terms of environmental services, it is better to avoid deforestation than to allow for deforestation to subsequently reforest, as

950-569: The Kerguelen Islands . Most of Antarctica is too cold and dry to support vegetation, and most of the continent is covered by ice fields or cold deserts. However, some portions of the continent, particularly the Antarctic Peninsula , have areas of rocky soil that support plant life. The flora presently consists of around 300–400 species of lichens, 100 mosses, 25 liverworts , and around 700 terrestrial and aquatic algae species, which live on

1000-449: The U.S. Geological Survey , who used photogrammetry methods based on a 1972 series of aerial photos, revealing the presence of 116 glaciers. In 2006, 109 of these glaciers were resurveyed with the existence of 97 verified and 12 thought to have disappeared. This showed that over just three decades there had been a large decrease in the amount of land area covered by glacial ice in these mountains. The scientific community has long recognized

1050-631: The carbon cycle , but they refer to slightly different things. A carbon pool can be thought of as the overarching term, and carbon sink is then a particular type of carbon pool: A carbon pool is all the places where carbon can be stored (for example the atmosphere, oceans, soil, plants, and fossil fuels). The amount of carbon dioxide varies naturally in a dynamic equilibrium with photosynthesis of land plants. The natural carbon sinks are: Artificial carbon sinks are those that store carbon in building materials or deep underground (geologic carbon sequestration ). No major artificial systems remove carbon from

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1100-400: The causes of climate change . In the context of climate change and in particular mitigation , a sink is defined as "Any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". In the case of non-CO 2 greenhouse gases, sinks need not store the gas. Instead they can break it down into substances that have

1150-498: The greenhouse gas carbon dioxide from the air, forests function as terrestrial carbon sinks, meaning they store large amounts of carbon in the form of biomass, encompassing roots, stems, branches, and leaves. Throughout their lifespan, trees continue to sequester carbon, storing atmospheric CO 2 long-term. Sustainable forest management , afforestation , reforestation are therefore important contributions to climate change mitigation. An important consideration in such efforts

1200-468: The mosquito , and even polar bears near the ocean. Tundra is largely devoid of poikilotherms such as frogs or lizards. Due to the harsh climate of Arctic tundra, regions of this kind have seen little human activity, even though they are sometimes rich in natural resources such as petroleum , natural gas , and uranium . In recent times this has begun to change in Alaska , Russia, and some other parts of

1250-443: The tree line or timberline. The tundra soil is rich in nitrogen and phosphorus . The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost , making the tundra soil a carbon sink . As global warming heats the ecosystem and causes soil thawing, the permafrost carbon cycle accelerates and releases much of these soil-contained greenhouse gases into

1300-570: The IPCC defines a sink as "Any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". Globally, the two most important carbon sinks are vegetation and the ocean . To enhance the ability of ecosystems to sequester carbon, changes are necessary in agriculture and forestry. Examples are preventing deforestation and restoring natural ecosystems by reforestation . Scenarios that limit global warming to 1.5 °C typically project

1350-583: The areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass ( Deschampsia antarctica ) and Antarctic pearlwort ( Colobanthus quitensis ), are found on the northern and western parts of the Antarctic Peninsula. In contrast with the Arctic tundra, the Antarctic tundra lacks a large mammal fauna, mostly due to its physical isolation from

1400-457: The atmosphere on a large scale yet. Public awareness of the significance of CO 2 sinks has grown since passage of the 1997 Kyoto Protocol , which promotes their use as a form of carbon offset . Soils represent a short to long-term carbon storage medium and contain more carbon than all terrestrial vegetation and the atmosphere combined. Plant litter and other biomass including charcoal accumulates as organic matter in soils, and

1450-449: The atmosphere than it releases. Globally, the two most important carbon sinks are vegetation and the ocean . Soil is an important carbon storage medium. Much of the organic carbon retained in the soil of agricultural areas has been depleted due to intensive farming . Blue carbon designates carbon that is fixed via certain marine ecosystems . Coastal blue carbon includes mangroves , salt marshes and seagrasses . These make up

1500-561: The atmosphere, creating a feedback cycle that changes climate. The term is a Russian word adapted from the Sámi languages . Arctic tundra occurs in the far Northern Hemisphere , north of the taiga belt. The word "tundra" usually refers only to the areas where the subsoil is permafrost , or permanently frozen soil. (It may also refer to the treeless plain in general so that northern Sápmi would be included.) Permafrost tundra includes vast areas of northern Russia and Canada. The polar tundra

1550-400: The atmosphere, thereby adding to greenhouse gas emissions . The methods for blue carbon management fall into the category of "ocean-based biological carbon dioxide removal (CDR) methods". They are a type of biological carbon fixation . Scientists are looking for ways to further develop the blue carbon potential of ecosystems. However, the long-term effectiveness of blue carbon as

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1600-477: The chilly atmosphere, but as a rule potential evapotranspiration is extremely low, allowing soggy terrain of swamps and bogs even in places that get precipitation typical of deserts of lower and middle latitudes. The amount of native tundra biomass depends more on the local temperature than the amount of precipitation. Carbon sink A carbon sink is a natural or artificial carbon sequestration process that "removes a  greenhouse gas , an aerosol or

1650-483: The climate system activated around 2 °C (3.6 °F) of global warming suggested that at this threshold, permafrost thaw would add a further 0.09 °C (0.16 °F) to global temperatures by 2100, with a range of 0.04–0.16 °C (0.07–0.29 °F) Antarctic tundra occurs on Antarctica and on several Antarctic and subantarctic islands, including South Georgia and the South Sandwich Islands and

1700-442: The future than keeping existing forests intact. It takes much longer − several decades − for the benefits for global warming to manifest to the same carbon sequestration benefits from mature trees in tropical forests and hence from limiting deforestation. Therefore, scientists consider "the protection and recovery of carbon-rich and long-lived ecosystems, especially natural forests" to be "the major climate solution ". Blue carbon

1750-612: The glaciers had lost about 50 percent of their total area. At this rate of melting, they predict that all of the glaciers in the Ahklun Mountains will be gone by the end of this century. Geological evidence show that during the Pleistocene era there were repeated glaciations that have carved out a large number of valley troughs . On the eastern side, these troughs contain networks of glacial lakes , some that are over 1,300 feet (400 m) deep and are dammed by terminal moraines . On

1800-411: The importance of glaciers as indicators of climatic change. In 2015, researchers analyzed aerial and satellite images from 1957, 1984, and 2009. They found that 10 out of 109 of the glaciers of the Ahklun Mountains originally mapped by the U.S. Geological Survey in the 1970s had completely disappeared. They also compared the size of the glaciers using aerial photographs and satellite images and found that

1850-488: The increased amounts of warmer rain are another factor which increases permafrost thaw depths. The IPCC Sixth Assessment Report estimates that carbon dioxide and methane released from permafrost could amount to the equivalent of 14–175 billion tonnes of carbon dioxide per 1 °C (1.8 °F) of warming. For comparison, by 2019, annual anthropogenic emission of carbon dioxide alone stood around 40 billion tonnes. A 2018 perspectives article discussing tipping points in

1900-839: The large-scale use of carbon dioxide removal methods over the 21st century. There are concerns about over-reliance on these technologies, and their environmental impacts. But ecosystem restoration and reduced conversion are among the mitigation tools that can yield the most emissions reductions before 2030. To enhance carbon sequestration processes in oceans the following technologies have been proposed but none have achieved large scale application so far: Seaweed farming , ocean fertilisation , artificial upwelling , basalt storage, mineralization and deep sea sediments, adding bases to neutralize acids. The idea of direct deep-sea carbon dioxide injection has been abandoned. Broad-base adoption of mass timber and their role in substituting steel and concrete in new mid-rise construction projects over

1950-425: The latter leads to irreversible effects in terms of biodiversity loss and soil degradation . Furthermore, the probability that legacy carbon will be released from soil is higher in younger boreal forest. Global greenhouse gas emissions caused by damage to tropical rainforests may have been substantially underestimated until around 2019. Additionally, the effects of afforestation and reforestation will be farther in

2000-563: The low hills along the major rivers. Blackpoll warblers are common breeders in conifer stands in river valleys. Beaver are abundant, supporting a large annual harvest. Sockeye salmon are the most abundant fish. Chum , king , silver salmon , and rainbow trout are also numerous. The average annual precipitation ranges from 19 to 25 inches (480 to 640 mm), while the average annual temperature ranges from 29 to 33 °F (−2 to 1 °C). The growing season extends approximately from May 15 to September 10. The glaciers were first mapped by

2050-478: The only subantarctic orchids; the royal penguin ; and the Antipodean albatross . There is some ambiguity on whether Magellanic moorland , on the west coast of Patagonia , should be considered tundra or not. Phytogeographer Edmundo Pisano called it tundra ( Spanish : tundra Magallánica ) since he considered the low temperatures key to restrict plant growth. More recent approaches have since recognized it as

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2100-607: The other continents. Sea mammals and sea birds, including seals and penguins, inhabit areas near the shore, and some small mammals, like rabbits and cats, have been introduced by humans to some of the subantarctic islands. The Antipodes Subantarctic Islands tundra ecoregion includes the Bounty Islands , Auckland Islands , Antipodes Islands , the Campbell Island group , and Macquarie Island . Species endemic to this ecoregion include Corybas dienemus and Corybas sulcatus ,

2150-413: The polar tundra areas. During the winter it is very cold, dark, and windy with the average temperature around −28 °C (−18 °F), sometimes dipping as low as −50 °C (−58 °F). However, extreme cold temperatures on the tundra do not drop as low as those experienced in taiga areas further south (for example, Russia's, Canada's, and Alaska's lowest temperatures were recorded in locations south of

2200-522: The potential diversity of climates in the ET category involving precipitation, extreme temperatures, and relative wet and dry seasons, this category is rarely subdivided, although, for example, Wainwright, Alaska can be classified ETw and Provideniya, Russia ETs , with most of the rest of the tundra fitting into the ETf subcategory. Rainfall and snowfall are generally slight due to the low vapor pressure of water in

2250-419: The quality of the grasslands overall, in turn increasing the amount of carbon retained in the humic material. They also deposit carbon directly into the soil in the form of biochar that does not significantly degrade back to carbon dioxide. Much organic carbon retained in many agricultural areas worldwide has been severely depleted due to intensive farming practices. Since the 1850s, a large proportion of

2300-418: The southern and western side, the valleys are broader and are interspersed with rolling uplands pierced by rugged massifs . In the lowlands, areas not reached by the glaciation, the principal geographic features are the moraines and ridges formed by thrusting ice. Tundra In physical geography , tundra ( / ˈ t ʌ n d r ə , ˈ t ʊ n -/ ) is a type of biome where tree growth

2350-444: The subject of habitat conservation programs. In Canada and Russia, many of these areas are protected through a national Biodiversity Action Plan . Tundra tends to be windy, with winds often blowing upwards of 50–100 km/h (30–60 mph). However, it is desert-like, with only about 150–250 mm (6–10 in) of precipitation falling per year (the summer is typically the season of maximum precipitation). Although precipitation

2400-412: The tree line). During the summer, temperatures rise somewhat, and the top layer of seasonally-frozen soil melts, leaving the ground very soggy. The tundra is covered in marshes, lakes, bogs, and streams during the warm months. Generally daytime temperatures during the summer rise to about 12 °C (54 °F) but can often drop to 3 °C (37 °F) or even below freezing. Arctic tundras are sometimes

2450-555: The world's grasslands have been tilled and converted to croplands, allowing the rapid oxidation of large quantities of soil organic carbon. Methods that significantly enhance carbon sequestration in soil are called carbon farming . They include for example no-till farming , residue mulching, cover cropping , and crop rotation . Forests are an important part of the global carbon cycle because trees and plants absorb carbon dioxide through photosynthesis . Therefore, they play an important role in climate change mitigation . By removing

2500-588: The world: for example, the Yamalo-Nenets Autonomous Okrug produces 90% of Russia's natural gas. A severe threat to tundra is global warming , which causes permafrost to thaw. The thawing of the permafrost in a given area on human time scales (decades or centuries) could radically change which species can survive there. It also represents a significant risk to infrastructure built on top of permafrost, such as roads and pipelines. In locations where dead vegetation and peat have accumulated, there

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